1. Field of the Invention
This invention relates to a pulsato generating system for producing sounds which provide a pulsato effect or the pulsato effect with a chorus effect.
1. Description of the Prior Art
By reproducing first and second phase rotating signals based on a musical signal, for example, from an electronic musical instrument by first and second speakers, it is possible to produce sounds which provide a pulsato effect. The first phase rotating signal rotates its phase at a relatively low speed in such a direction 0-.pi./2-.pi.-3.pi./2 that the amount of phase shift gradually increases. The second phase rotating signal rotates its phase at the same speed as the first phase rotating signal in such a direction .pi.-.pi./2-0-3.pi./2 that the amount of phase shift gradually decreases.
When first, second and third sequentially phase inverting signals based on a musical signal, for example, from an electronic musical instrument, are respectively reproduced by first, second and third speakers, it is also possible to produce sounds which provide a pulsato effect. The first sequentially phase inverting signal sequentially inverts its phase between 0 and .pi. at a relatively low speed and undergoes such an amplitude change that its amplitude is maximum at the center between the two phase inverting positions and minimum at the phase inverting positions. The second sequentially phase inverting signal sequentially inverts its phase between .pi. and 0 in the opposite phase relation to the first sequentially phase inverting signal but at the same speed as the first sequentially phase inverting signal and undergoes the same amplitude change as the latter. The third sequentially phase inverting signal sequentially inverts its phase between .pi./2 and 3.pi./2 while being shifted by .pi./2 relative to the first and second sequentially phase inverting signals but at the same speed as the first and second sequentially phase inverting signals. The third sequentially phase inverting signal also undergoes the same amplitude change as the first and second sequentially phase inverting signals.
Further, when a composite signal, which is composed of a musical signal obtained, for example, from an electronic musical instrument, and at least one frequency-modulated signal obtained by frequency modulating the musical signal with a sine-or cosine-wave, i.e. a sinusoidal wave, signal of a relatively low frequency, are reproduced by a speaker, it is possible to produce sounds which provide a chorus effect. Moreover, if the abovesaid first and second phase rotating signals are obtained from the abovesaid composite signal used as an input signal and respectively reproduced by the first and second speakers, it is possible to produce sounds which provide the pulsato effect together with the chorus effect.
Further, if the aforementioned first, second and third sequentially phase inverting signals are obtained from the above said composite signal used as an input signal and respectively reproduced by the first, second and third speakers, it is possible to produce sounds which provide the pulsato effect together with the chorus effect.
Conventional types of pulsato generating systems are defective in that means for generating the abovesaid phase rotating signals, means for the abovesaid sequentially phase inverting signals and means for generating the abovesaid composite signal providing the chorus effect are all complicated and bulky.